Treatment with albendazole sensitizes MM and SCLC cells to ionizing radiation. Radiosensitization by albendazole was assessed on the basis of clonogenic cell survival assays. H446 (A), H1530 , A375 (C) and A2058 (D) cells were treated with 0 (О), 100 (□), or 500 nM (Δ) ABZ for 12 hr then irradiated as indicated. Cells were stained with crystal violet after being cultured for approximately 2 weeks. Points, average of experiments each plated in duplicate. Bars, SEM. *, P < 0.05.